What is the difference between Drill Down and Change Level? Great question!
Change Level will not filter the data, but will only show it at a different hierarchy level. Drill Down will filter and change the level as well. For example, if you change the level to a month on a chart showing 2017 and 2018 at the year level, you’ll get a chart showing all months in 2017 and 2018. However, if you drill down on that same chart under 2018, you’ll only see the months of 2018!